Most current assessment of Chalk River NRU reactor allows for revised
guidance on timeline for return to service
TORONTO, July 8 /CNW/ - Atomic Energy of Canada Limited (AECL) today
announced that as a result of the most recent data from the ongoing assessment
of the National Research Universal (NRU) reactor condition and the development
of a critical path for the various repair options, it is now clear that the
NRU will not return to service before late 2009.
AECL released this information at a media briefing today as part of its
commitment to public disclosure of activities related to the repair of the NRU
at Chalk River, Ontario.
"Returning the NRU to service to support the production of medical
isotopes for Canadian patients and healthcare practitioners is our primary
objective", said AECL's President and CEO Hugh MacDiarmid. "We have a
dedicated team working around the clock to bring the NRU back to operation as
quickly and as safely as possible. However, it is a complex task with many
variables", he said.
The duration of the shutdown continues to be founded on the best evidence
available, including the most up-to-date analysis of the heavy water leak
site, vessel condition, repair strategies, and critical path requirements for
restart after an extended shutdown.
"We have identified three phases of our return to service <a href="http://files.newswire.ca/661/NRU_Plan_ENG.pdf">plan</a>. Today we
are progressing toward the end of phase one which involves a comprehensive
condition assessment of the reactor, the development and testing of several
repair options, and overall planning and critical path development", said
MacDiarmid. "This work will contribute to a decision on the preferred repair
strategy to pursue in phase two."
A decision on the repair method is expected in the next few weeks. Phase
two of the return to service plan, effecting the actual repair, is estimated
to take in the order of two months depending on the method determined,
regulatory considerations, and further analysis of the extent of the repair
required. Phase three, restarting and testing the reactor, is estimated to
take an additional two months, based on AECL's previous experience of
refilling, refuelling and start-up of the reactor in 1992.
To date, the leak site at the base of the reactor, which is approximately
nine meters from the closest access location, has been thoroughly analysed.
More than 60 per cent of the reactor vessel's circumference has been surveyed
using remote, non-destructive methods. The examination has revealed thinning
of the wall at the leak site, and identified a total of nine areas of
AECL metallurgical and material experts are working with external
engineering firms having remote repair capability to determine the best
methods for cleaning and repairing the reactor vessel.
Mock-ups of the affected area of the NRU vessel have been constructed to
provide necessary on-site testing and training for vessel inspection and
repair work, and a full-height mock up of a section of the reactor is
currently being built.
"Chalk River staff have great technical expertise in the areas of remote
inspection, material science, corrosion, and critical path development," said
Bill Pilkington, AECL's Senior Vice-President and Chief Nuclear Officer. "All
of the evidence to date supports the view that the NRU can be successfully
returned to service. We have the experience and know-how to bring the NRU back
into service safely and in the shortest time possible."
Further guidance on a return to service date will be provided as more
data is collected and analyzed, and the decision is made about the repair
technique and extent of required repairs. AECL continues to work very closely
with the Canadian Nuclear Safety Commission (CNSC), and CNSC safety inspectors
are directly involved at the Chalk River site.
There is no threat to workers, the public, the environment or nuclear
safety related to this event. More information on the repair and status
updates on the NRU is available at www.nruCanada.ca
For further information:
For further information: Dale Coffin, Director, Corporate
Communications, AECL, 1-866-886-(AECL) 2325